Operation of luminous tubes



June 23, 1931. Q 5 TREACY 1,811,100

OPERATION OF LUMINOUS TUBES Filed NOV. 6, 1928 fill/Ill!!!- INVENTOR Y" 9 "TTORNEY Patented June 23, 1931 UNITED STATES PATENT OFFICE CYRIL S. TREACY, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO INTERNATIONAL NEON COMPANY, INCORPORATED), OF NEW YORK, N. Y., A CORPORATION OF NEVADA OPERATION OF LUMINOUS TUBES Application filed November 6, 1928. Serial No. 317,681.

I This invention relates to signs comprising luminescent gas-conducting display tubes and to a method of operating the same and provides improvements therein.

Tubes which develo a flicker, or striations, have not hereto ore been regarded as merchantable tubes for sign work. ,I' have discovered that this flicker develops after a period of current flow, and that if the current is interrupted and again supplied to the tube the tube will burn steady for the same, or approximately the same period, beforethe flicker again develops.

Applying this discovery, I provide by the present invention, a useful sign, and method of operating it, making use of tubes which flicker under ordinary conditions, and am further, able to provide a sign and tubes having the important practical advantages over signs heretofore in use, of having greater life and serviceability and of having light internal electrodes admitting of shipment and greater ease and security of handling. An embodiment of the invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a somewhat diagrammatic View of a sign comprising a tube which flickers under ordinary conditions, and

Fig. 2 is an enlarged sectional view show-' ing one end of a tube and an electrode.

Referring to said drawings, numeral 10 designates a luminescent gas-conducting tube, which will flicker when current is passed therethrough for some time without interruption, and 12 designates electrical means for intermittently supplying current to said tube.

Said tube 10 is preferably made with internal electrodes 14, which electrodes may with advantage be made very small and light. The electrode support 15 may be also relatively small and light. With such electrodes and electrode supports, the unsupported weight is small, and consequently the tendency of the electrodes to fracture the tubes when the tubes are subjected to shock is greatly diminished, thereby favoring the adaptability thereof for shipment.

These electrodes may be made of ordinary materials, such as common metals (iron, copper, steel, nickel, etc.), carbon, and in fact of any desired material. With small electrodes, however, using normal current densities, and with usual gas pressures withlgreater than in the tubes, the sputtering is with larger electrodes having t rent density.

Through a range of gas pressures, display tubes develop flickering after the current has passed for a period of time.

, I have found that "f the current is interrupted at or before the time that the flicker begins, and current again passed throu h the electrodes, that the tube will burn steady for another period equal or substantially equal to the first period, and so on. According to the. present invention, therefore, I interrupt the current periodically, so that the periods during which the current flows do not exceed the periods in which the flickers appear. Thereby the tubes burn or are luminescent intermittently without flicker.

Any suitable means may be provided for e same ourintermittently supplying current to the electrodes in the manner described. These means'may conveniently comprise a transformer 20 having a high tension secondary 22 connected by suitable conductors 24, 25 to the electrodes 14, and with a primary 28 connected by suitable conductors 31 to a suitable source of current, as for example mains 33, 34 or an ordinarylow potential house or commercial circuit. An interrupter 37 of any suitable type is provided and conveniently inserted in one of the conductors connected with the secondary winding 28. The interrupter 37 has a period, or is adjusted to have a period of interruption which is preferably somewhat less than, and not greater than the period in which the tubes burn before the flicker appears, for example 1 to 10 seconds. An ordinary hot-wire thermostat interrupter of the so-called flasher type is here illustrated, though any other sultable type of interrupter could be employed.

Tubes according to the present invention can he used very advantageously "for horders and units such as individual letters.

ihe method of operating signs comprising tubes which have a period in which a flicker a pears, as heretofore described is to supp y current intermittently to said tubes, the duration of the supply of current being preferably less than and not greater than the period in which the flicker appears, 1-10 seconds, for example.

The invention may receive various other embodiments than that herein specificaliy illustrated and described.

What is claimed is:

v 1. A luminescent sign, comprising a gasconducting display tube of the internal electrode type, having a period of the order of seconds, at the end of which flickers appear after illumination, and means for intermit- .tently supplyingcurrent to said tube for periods not greater than the period in which said flickers appear.

2. A sign according to claim 1, further including small electrodes with an area corresponding to a high current density.

3. A method of operating luminescent gasconducting display tubes of the internal electrode type having a period of the orderof seconds, at the end of which flickers appear after illumination, comprising intermittently supplying current to said tubes for periods not greater than the period in which said flickers appear.

In witness whereof, I have hereunto signed my name.

.CYRIL S. TBEACY.

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